Serial MR Imaging of Annular Tears in Lumbar Intervertebral Disks.

Fletcher M Munter, Bruce A Wasserman, Hsiu-Mei Wu, David M Yousem

Annular tears of lumbar intervertebral disks are found in both symptomatic and asymptomatic persons; therefore, it is difficult to determine whether these findings indicate acute abnormality. Our purpose was to determine whether the MR imaging findings of tears (ie, hyperintensity and contrast enhancement) of the annulus fibrosus persist or resolve over time. A radiologic database was searched for spinal MR imaging examinations noting annular tears. Eighteen patients were identified who had undergone more than one spinal MR imaging study. The images were reviewed for presence or absence of annular tears, defined as an area of hyperintensity on T2-weighted images or enhancement in the posterior annulus, separate from the nucleus pulposus. Annular tears were observed at 29 levels in 18 patients. Two tears developed during the follow-up interval. When contrast-enhanced images were obtained during serial examinations, 10 (100%) of 10 enhancing annular tears persisted on the follow-up contrast-enhanced T1-weighted images (mean interval, 17.2 months; SD, 12.3 months). High signal intensity on T2-weighted MR images was noted in 26 (96%) of 27 tears initially and persisted in 23 (88%) of 26 (mean interval, 21.9 months; SD, 15.0 months). Hyperintensity on T2-weighted MR images and enhancement of annular tears could not be used to determine the tears' acuity over the range of follow-up provided in this study.